To eliminate 'step response' by varying an impressed voltage so as to converge on a rather large voltage at the beginning of write-in and on a voltage close to a desired value at the end, and thereby obtaining a highly contrasted stable display.
A liquid crystal display element is equipped with an active element and employs as the liquid crystal material a chiral smetic C phase or its secondary layer liquid crystal. Then, a signal voltage and a common voltage are varied so that at the start of write-in time, a voltage is applied higher than the one corresponding to a desired light transmitting quantity in an impressed voltage-light transmittance curve, and that at the end of the write-in time, a voltage is applied close to the one corresponding to a desired light transmitting quantity. In other words, in 2/3 of the write-in time, the light transmittance state reaches only up to the curve (c); however, so long as writing is by a rather large voltage, the light transmittance state ultimately reaches a value close to the desired state. Such driving eliminates excessive writing in which the saturation part of the curve (a) is reached, so that increase in writing quantity can be contrived effectively.
SAISHIYU TATSUO
OKUMURA HARUHIKO
MIZUTANI YOSHIHISA
IIDA RIEKO
TAKATO TAKAKI
FUJIWARA HISAO
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